JP2003249739A - Method of manufacturing prepreg, prepreg obtained with the same method, method of manufacturing copper foil with insulation layer, and copper foil with insulation layer manufactured with the same method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prepreg using a thin skeletal material which can assure excellent boring property with laser and also provide a method of stably manufacturing copper foil with thin insulation layer. <P>SOLUTION: A method of manufacturing prepreg for manufacturing a printed wiring board in which a thermosetting resin is impregnated into a skeletal material. This method includes following processes. (1) Liquid resin film forming process to form a liquid resin layer on the flat surface of a work using a liquid thermosetting resin. (2) Preliminary drying process to convert the relevant liquid resin layer into a dried resin layer. (3) Skeletal material preliminary bonding process for the dried resin layer with skeletal material by thermally depositing the skeletal material to the dried resin layer on the flat surface of the work. (4) Resin impregnation process for impregnating the resin element to the relevant skeletal material by heating the dried resin layer with skeletal material at the temperature which diffuses again the resin. (5) Cooling process for immediately lowering temperature, upon completion of impregnation of resin, to maintain the half-hardened condition of the thermosetting resin impregnated into the skeletal material in view of obtaining again the prepreg condition. Moreover, a method of manufacturing a copper foil with insulation layer with the similar method is also provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg manufacturing method, a prepreg manufacturing apparatus, and a prepreg obtained by the manufacturing method.

[0002]

2. Description of the Related Art Conventionally, prepreg has been used as an interlayer insulating material for printed wiring boards used in the fields of electric and electronic industries. The prepreg includes paper-phenol prepreg in which a phenolic resin is impregnated in a skeleton material, glass-epoxy prepreg in which an epoxy resin is impregnated in a glass cloth which is a skeleton material, and a polyimide resin skeleton material. There are various products such as glass-polyimide prepreg impregnated with glass cloth. In recent years, due to the trend toward thinner printed wiring boards, there has been a demand for a thin prepreg that is a constituent material of the interlayer insulating layer of the printed wiring board and has high reliability.

As a method of manufacturing a prepreg, a manufacturing method having a characteristic is adopted by each manufacturer. Explaining the basic structure of a general prepreg manufacturing apparatus except for the accumulator and other auxiliary equipment, it can be said that the manufacturing method shown in FIG. 5 is most widely adopted. That is, the resin composition with which the skeleton material is impregnated is manufactured into a varnish by using the varnish reaction kettle 17 in a formulation having various characteristics. This varnish is sent to the circulation tank 18, and this varnish is sent from the circulation tank 18 to the impregnation vat 20 in the step of impregnating the skeleton with the resin and circulates.

In the step of impregnating the skeleton with resin, a means for continuously feeding the skeleton 5 by axially supporting a skeleton roll is provided, and the skeleton 5 fed from this is generally a pre-soaking bat. After passing through 19, the skeleton material 5 is formed in the impregnation vat 20 by either a dip method or a kiss coat method.
When the impregnated resin is impregnated into the impregnated pad 20, the impregnated resin is dried to a semi-cured state (B stage) by using a heating method such as a hot air circulation method or a heat radiation method. It is run in the drying tower 21 arranged at, finally cooled, and wound as a prepreg roll 22 and collected.

In the prepreg manufactured by such a method, when a woven skeleton material such as a glass cloth is used, there is a problem such as bending of the cloth, but a prepreg having a thickness of about 20 μm is used and the prepreg is 30 μm. It has become possible to manufacture thick prepregs, and they have become widely accepted in the market.

[0006]

However, when a prepreg using a woven cloth type skeleton material such as glass cloth is used, a via hole which requires carbon dioxide laser drilling after forming a copper clad laminate. There was a problem in forming holes. That is, when attempting to make a hole in a copper clad laminate using a carbon dioxide laser, the workability of the glass cloth in the interlayer insulating layer is poor, and the shape of the inner wall of the via hole after hole formation is deteriorated. .

In order to solve such a problem, a non-woven type skeleton material such as a glass non-woven fabric or an aramid non-woven fabric has been used in place of the cross type skeleton material. Certainly, by making the skeleton material a non-woven fabric type,
The shape of the inner wall surface such as the via hole formed by using the carbon dioxide gas laser has become remarkably excellent, which has led to a great technological advance.

However, the non-woven fabric is not a cloth type in which warp yarns and weft yarns are alternately woven, but it is considered that it is made by pressing glass fibers or aramid fibers etc. into a sheet like a felt fabric. Is. Therefore, the strength of the non-woven fabric type skeleton itself is lower than that of the cross type skeleton, and the resistance to external stress load such as tension is reduced.

As a result, when the non-woven fabric is impregnated with resin by the method using the vertical type drying tower as described above and is dried, when the non-woven fabric impregnated with the required amount of resin travels through the drying tower, The weight of the impregnated resin will be applied to the nonwoven fabric, and the thinner the nonwoven fabric, the more the impregnated resin will break in the drying tower before the semi-cured state and the process will stop, resulting in a significant production yield. It was supposed to lower. It has been said that such a phenomenon is very likely to occur when the nonwoven fabric used as the skeleton has a nominal thickness of 70 μm or less, and it is almost impossible to use the nonwoven fabric having the nominal thickness of 30 μm or less as the skeleton.

In the ordinary resin impregnation method as described above, even when a woven cloth such as glass cloth is used as the skeletal material, naturally, when the woven cloth of 20 μm or less is impregnated with the resin and dried, Of course, it is easy to break in the vertical drying tower, and it is not possible to secure the safety fiber of the process. However, the case of using the woven fabric is more difficult to break than the case of using the non-woven fabric, and is not much more reliable than the case of using the thick woven fabric.

From the above, in the market, as a prepreg capable of ensuring the above-mentioned carbon dioxide laser drilling property,
It has been awaited to establish a manufacturing method capable of stably producing a prepreg having an unprecedented thinness by using a nonwoven fabric or a nonwoven fabric as a skeletal material.

[0012]

The inventors of the present invention have made earnest studies as a result, and as a result of using the method for producing a prepreg as shown below, the stability of the prepreg using a nonwoven fabric of 70 μm or less as a skeleton material is stabilized. It was conceived that the production and the stable production of the prepreg using the ultrathin glass cloth of 30 μm or less as the skeleton can be performed.

According to the claims, there is provided a method of manufacturing a prepreg used for manufacturing a printed wiring board in which a skeletal material is impregnated with a thermosetting resin, which is characterized by including the following steps (1) to (3). It is used as a method for manufacturing prepreg. Each step will be described step by step with reference to FIGS. 1 to 3.

In the step, a liquid thermosetting resin is used to form a liquid resin layer 3 as a film having a predetermined thickness on a flat work plane 2 as schematically shown in FIG. 1 (1). It is a step of forming a liquid resin film to be formed. Here, the liquid thermosetting resin is an epoxy resin compound or the like obtained by mixing an epoxy resin, a curing agent, a curing accelerator and the like with a solvent, and to the extent that it can be applied to the work plane 2. It has a low viscosity. This liquid thermosetting resin
It becomes the resin with which the skeleton material is impregnated.

The work plane 2 is a plane mainly made of a metal material such as copper, titanium, aluminum, stainless steel, etc., and as will be apparent from the following manufacturing method, in order to bring the resin into a semi-cured state. What has heat resistance with respect to the heat in the heating operation to be performed may be used. For example, the surface of aluminum may be treated with a fluororesin or the like to withstand a temperature of 200 ° C. or higher.

Here, using a liquid thermosetting resin,
The method of forming the liquid resin layer 3 as a coating having a predetermined thickness on a flat work plane does not require any particular limitation. A method of applying a uniform thickness using a coating machine or a method of spreading a certain amount of resin placed on the work plane 2 to a uniform thickness with a jig such as a squeegee may be used. . Also,
The expression "as a film of a predetermined thickness ..."
In the prepreg that has been used so far, it is common to impregnate the same weight of resin per unit weight of the skeleton, but depending on the thickness of the non-woven or woven skeleton and the type of skeleton. This is because it is difficult to define a clear numerical value at this stage because the amount of resin used is different. It is described here that it is clear at this stage that when the aramid nonwoven fabric is used, the weight of the aramid nonwoven fabric in the prepreg is 20 wt% to 40%.
The weight of the glass non-woven fabric in the prepreg is adjusted to be 20 wt% to 50 wt% when the glass non-woven fabric is used. It is preferable in terms of quality stabilization such as migration performance.

The step is a preliminary drying step in which the liquid resin layer 3 formed on the work plane 2 is dried as it is as shown in FIG. 1 (2) to form a dry resin layer 4. Is. This step has a very important technical meaning in the present invention. In this step itself, the liquid resin layer 3 formed on the work plane 2 is dried as it is to form the dry resin layer 4. Therefore, the liquid resin layer 3 is heated for a short time or exposed to the atmosphere. The solvent used in preparing the liquid thermosetting resin is removed by performing air-drying treatment in which it is exposed for a certain period of time or combining both methods. Therefore, the dry resin layer 4 is in a state in which the solvent is removed, is in an uncured state in which curing has not progressed if only air drying is performed, and is in a semi-cured state if heated and dried. Is. At this time, the weight loss due to heating when the solvent of the liquid thermosetting resin is removed is 0 wt%.
It is preferably in the range of 10 wt%. The larger the value of this heating loss, the larger the amount of the solvent contained, and the lower the viscosity. The heating loss of 0 wt% is included here because it is possible to prepare a liquid thermosetting resin that does not use a solvent at all. Therefore, strictly speaking, when a solvent is used, the heating loss is 0.1 wt% to 10 wt%.
It is preferable to set it as the range.

It is assumed that the skeleton material is directly placed on the surface of the liquid resin layer 3 on the work plane 2 without impregnating the liquid resin layer 3 using a solvent in a dry state, and the skeleton material is impregnated with the resin and heated. When attempting to dry the resin, the bubbles generated by the removal of the solvent remain in the prepreg as if they were trapped between the fibers of the skeleton, and it is not possible to obtain a good prepreg. . Therefore, when the weight loss due to heating is 10 wt% or more, it takes a long time to remove the solvent by using air drying, and it becomes difficult to sufficiently remove the solvent, and the probability of occurrence of bubbles increases. . On the other hand, when the loss on heating is 0.1 wt% or less, curing progresses easily when heated, and after the resin described below is re-fluidized, it remains in a semi-cured state suitable for prepreg. Will be difficult.

The process performed after the liquid resin layer 3 is changed to the dry resin layer 4 is, as schematically shown in FIG.
This is a skeleton material pre-bonding step in which the skeleton material 5 is superposed on the surface of the dry resin layer 4 on the work plane 2, preheated and pressure-bonded to form the skeleton material-containing dry resin layer 7. In this pre-bonding step of the skeleton material, a non-woven fabric or a woven cloth 5 as a skeleton material is formed on the surface of the dry resin layer 4 on the work plane 2.
In the process of laminating, the non-woven fabric or woven fabric 5 which is a skeleton material is simply laminated to the surface of the dry resin layer 4 as described in “Preheating and crimping”, and even resin impregnation is performed. Does not.

In order to preheat and press-bond the skeleton material 5 to the surface of the dry resin layer 4 using a heating roll 6, the skeleton material 5 is evenly and uniformly applied to the surface of the dry resin layer 4 without wrinkles or other defects. A non-woven fabric or a woven fabric 5, which is a skeleton material, is placed on the surface of 4, and is momentarily pressed by a heating press plate or the like at a low pressure so as to be evenly attached. The one obtained here is referred to as a “dry resin layer with a skeleton material” for the sake of explanation in this specification. In this way, by attaching the skeleton material to the semi-cured resin layer once, it is easy to form a good flat state without wrinkles, breakage, etc. of the skeleton material. Since the resin is not impregnated in the state of being pressed by the plate, resin adhesion to these processing devices is prevented and repeated continuous operation is possible.

The thickness of the skeleton material 5 used here is not particularly limited, but considering the object of the present invention,
Nonwoven fabric with a nominal thickness of 70 μm or less, nominal thickness of 30 μm
The following woven fabric will be used. Also, the type of the non-woven fabric or woven fabric can be used as long as it is a material such as aramid fiber or glass fiber that can be used for a prepreg of a printed wiring board. In particular, in the case of a woven fabric, it is preferable to use an SP cloth in which the fibers constituting the woven fabric are opened flatly and the cross-sectional shape of the longitudinal and lateral strands is flattened, considering the laser drilling processability. It will be more preferable. Furthermore, in order to improve the wettability with the resin, the surface of the fibers constituting these skeleton materials should be treated with a silane coupling agent by an amino-based silane coupling agent tower to prevent the occurrence of voids and delamination of the interface. From the viewpoint of, it is preferable.

Then, in the process, as schematically shown in FIG. 3 (4), the dry resin layer 7 with the skeleton material is formed on the work plane 2.
Is a resin impregnation step of heating the resin of the dry resin layer 4 at a temperature at which the resin can be reflowed while the above is placed, and impregnating the frame material 5 with the thermosetting resin component. As is clear from the steps up to this point, no extra load is applied to the skeleton itself even if a thin skeleton is used. Also in this resin impregnation step, while the dried resin layer 7 with the skeleton material is placed on the work plane 2, the resin is heated at a temperature at which the resin can reflow to impregnate the skeleton material 5 with the thermosetting resin component. Of. Therefore, the weight of the impregnated resin does not give a load to the skeleton itself, so that the skeleton is not pulled by the resin weight, and even if it is thin, it is not broken.

In the resin impregnation step, the skeletal material-added dry resin layer 7
The resin forming the dry resin layer is heated at a temperature at which it does not cure only by reflowing. The re-fluidized resin enters the gaps between the fibers of the skeleton material 5 and is sucked up by the skeleton material due to the capillary phenomenon.
As far as the inventors of the present invention confirm, the refluidized resin permeates the skeleton material 5 and wraps the entire skeleton material 5, so that the same impregnation state as that of the conventional prepreg can be obtained. is there.

Upon completion of the resin impregnation, as a step, as shown schematically in FIG. 3 (5), the temperature is lowered immediately to prevent the impregnated thermosetting resin from being completely cured.
A temperature lowering step is provided to maintain the semi-cured state of the thermosetting resin impregnated in the skeleton material 5 and bring it into the prepreg state. Although referred to as a temperature lowering step here, the air blower device 10 as shown in FIG.
May be used for cooling with wind. In particular, it is not necessary to perform the temperature lowering operation using an apparatus capable of discharging cold air cooled to room temperature or lower.

When the temperature lowering operation is completed, the prepreg 1 in which the skeletal material 5 is impregnated with the thermosetting resin and the thermosetting resin is in the semi-cured state is obtained.
As described above, since the skeleton 5 can be impregnated with the resin while being placed on the flat surface of the resin impregnation workbench, the weight of the impregnated resin is not applied to the skeleton itself. As a result, even if the skeletal member 5 becomes extremely thin,
This makes it possible to eliminate a process defect in which the skeleton material 5 is pulled by the resin weight and is broken.

In carrying out the prepreg manufacturing method described above, it is desirable to use the continuous manufacturing method as described below from the viewpoint of extremely improving the production efficiency. FIG. 4 schematically shows a production line for carrying out this continuous production method. Hereinafter, description will be given with reference to this figure.

That is, "a metal belt that runs endlessly on an endless track, a resin supply means for forming a thermosetting liquid resin layer on the metal belt, and a pre-drying for making the liquid resin layer a dry resin layer. Means, skeleton material supplying means for continuously supplying skeleton material to the production line, skeleton material pre-bonding means for preliminarily crimping the skeleton material to the dry resin layer, preliminarily crimping the skeleton material to the dry resin layer 2. A manufacturing line comprising a resin impregnating means for heating the formed portion to impregnate the resin, a temperature lowering means for performing a temperature lowering operation after completion of the resin impregnation to obtain a prepreg state, and a means for collecting the completed prepreg. The manufacturing apparatus used for carrying out the method for manufacturing a prepreg according to claim 1, wherein the metal belt has a temperature drop from the resin supply means in the process from the primary side to the secondary side. At least consistently traveling up to the step, the resin supply means continuously supplies a liquid thermosetting resin onto the metal belt to form a liquid resin layer having a uniform predetermined thickness on the metal belt. A resin dispenser that can be formed is arranged on the primary end of the metal belt, and the liquid resin layer on the metal belt is used as a dry resin layer on the secondary side of the resin supply means. As a preliminary drying means, a drying zone for performing heat drying or air drying is arranged, and the skeleton material is continuously fed from the skeleton material raw material roll to the secondary side of the preliminary drying means in synchronization with the traveling speed of the metal belt. A skeleton material supplying means is arranged, and the skeleton material supplied from the skeleton material supplying means is heated and pressure-bonded to the surface of the dry resin layer on the metal belt on the secondary side of the skeleton material supplying means by using a heating roll. You A skeleton material pre-adhesion means is provided, and the portion of the dry resin layer to which the skeleton material is pre-adhered is heated to a temperature not higher than the curing temperature of the resin on the secondary side of the skeleton material pre-adhesion means, and the thermosetting resin Fluidize,
A heating zone for impregnating the skeleton laminated with fluidized resin is provided as a resin impregnating means, and the secondary side of the resin impregnating means is cooled to a prepreg state after the resin impregnation is finished or forced cooling. By doing so, the cooling zone for maintaining the semi-cured state of the thermosetting resin impregnated in the skeletal material to the state of the prepreg is arranged as the temperature lowering means, and the completed prepreg is rolled on the secondary side of the temperature lowering means. A continuous prepreg manufacturing apparatus used for manufacturing a printed wiring board in which a skeletal material is impregnated with a thermosetting resin, characterized in that a winding device or a cutting device serving as a cut sheet is arranged as a means for collecting the prepreg. It is.

At the center of the continuous manufacturing apparatus 11, a metal belt 12 which runs endlessly on an endless track is arranged. The metal belt 12 travels at least consistently from the resin supply means to the temperature lowering means in the process from the primary side to the secondary side. The term "at least consistent" is used because the running area of the metal belt may vary depending on the design of the device. The metal belt 12 referred to here is a metal belt having flexibility such that it can run endlessly on an endless track like a belt conveyor. Therefore, as long as it has a heat resistance of 200 ° C. or higher, copper, copper alloy, aluminum, stainless steel, in particular, the kind of metal material constituting the metal belt is not limited.
However, in order to have flexibility, a metal strip or metal foil having a certain thickness is used, and a thickness of 50 μm to 400 μm is used from the viewpoint of forming a uniform plane. .

Further, the surface of the metal belt 12 may be a smooth smooth surface or may have irregularities to some extent. A certain degree of unevenness is a degree of roughness of an adhesive surface used as a surface to be adhered to a base resin of an electrolytic copper foil, specifically, a surface roughness (Rz) of 5.0 μm to 24.0 μm.
It is preferably about m. If the metal belt 1 has a certain degree of unevenness, the liquid thermosetting resin described below is added to the metal belt 1.
2 and the liquid resin layer 3 on the metal belt 12 continuously supplied.
When forming the, even if the viscosity of the liquid resin becomes low,
The lateral flow of the resin on the metal belt 12 can be prevented, and the shape retention performance of the formed liquid resin layer 3 is excellent. The roughness of the surface of the metal belt 12 is Rz = 2.
When the thickness becomes 4.0 μm, the thickness of the liquid resin layer 3 described below cannot be made uniform, and when the roughness of the irregularities on the surface of the metal belt 12 becomes Rz = 5.0 μm, the shape of the liquid resin layer 3 is maintained. The performance is the same when it is a mirror surface.

First, a resin supply means is arranged at the primary end of the metal belt 12. In the present specification, the resin supply means continuously supplies a liquid thermosetting resin onto the metal belt 12, and the metal belt 1
The resin dispenser 13 is capable of forming the liquid resin layer 3 having a uniform and predetermined thickness on the resin dispenser 13. The resin dispenser 13 mentioned here has a function of continuously supplying a liquid thermosetting resin onto the metal belt 12 and a function of forming a liquid resin layer 3 having a uniform predetermined thickness on the metal belt 12. Even an integrated device such as an edge coater or a lip coater capable of simultaneously performing the above is described as a concept including both devices that are regarded as one unit that performs these functions separately.
Any device that can perform the same function can be used without problems.

Then, a portion of the metal belt 12 where the liquid resin layer 3 having a uniform thickness is formed is provided with a drying zone 14 as a preliminary drying means on the secondary side of the resin supply means. The liquid resin layer 3 on the metal belt 12 is the dry resin layer 4. In this drying zone, when the line speed is high, it is possible to adopt the heat drying as shown in FIG. 4 for quick drying, and when the line speed is sufficiently low, it is possible to adopt the air drying. The term "air-dried" is used to mean that it is simply left in the atmosphere, or that the air blown out by a fan is blown.

Next, a skeleton material supplying means for continuously supplying the skeleton material 5 into the manufacturing line is arranged on the secondary side of the preliminary drying means. This skeleton material supply means continuously supplies the skeleton material 5 continuously fed from the skeleton material raw material roll 15 to the surface of the metal belt 12 which has become the dry resin layer 4, and superimposes it. is there. At this time, the feeding speed of the skeleton material 5 from the skeleton material raw material roll 15 and the traveling speed of the metal belt 12 are made to coincide with each other and synchronized. This is for sticking the skeleton material in a plane and without wrinkles.

Then, a skeleton material pre-bonding means is arranged on the secondary side of the skeleton material supply means. This skeleton material pre-adhesion means continuously heat-bonds the skeleton material 5 supplied from the skeleton material supply means to the surface of the dry resin layer 4 by using a heating roll 6 to form a skeleton material-containing dry resin layer 7. It is to make it a state. When the skeleton material 5 is pressure-bonded by the heating roll 6, only the resin on the surface layer of the dry resin layer 4 is reflowed by the heat of the heating roll 6 and the skeleton material 5 sticks without any problem, but the dried resin fluidized through the skeleton material 5 is used. The pressure is set so low that the resin of the layer 4 does not seep out. So-called temporary adhesion is performed. This is because if the resin oozes out, it adheres to the surface of the heating roll 6 and continuous production becomes impossible.

Next, on the secondary side of the preliminarily adhering means for the skeleton material, the portion in the state of the dry resin layer with skeleton material 7 is heated at a temperature not higher than the curing temperature of the resin to re-add the thermosetting resin. The heating zone 16 for fluidizing and impregnating the skeleton material 5 to which the fluidized resin is bonded is provided as a resin impregnating means. Since the resin impregnation is performed here, it is necessary that the entire thermosetting resin forming the dry resin layer 4 be refluidized. Therefore, a so-called heating furnace is adopted as the resin impregnating means, and the heating system is not particularly limited. When sufficient refluidization of the resin occurs in the heating zone 16 of the resin impregnating means, the skeleton material 5 sucks up the refluidized resin within a short time, and impregnation can be performed.

The part where the resin is impregnated into the skeleton 5 is
Upon exiting the heating zone 16 as a resin impregnating means, the temperature is immediately lowered, and the prepreg is formed. Therefore, the temperature lowering means for performing the temperature lowering operation is arranged on the secondary side of the resin impregnating means, and is forcibly cooled by allowing air to cool or by using a fan to blow air. In FIG. 4, the air blower device 10 is described as an example.

Finally, on the secondary side of the temperature lowering means, a winding device for making the completed prepreg 1 into a roll or a cutting device as a cut sheet is arranged as a means for collecting the prepreg 1. As described above, the skeleton material 5
Thus, it becomes possible to continuously manufacture the prepreg 1 used for manufacturing a printed wiring board in which the thermosetting resin is impregnated. By using this apparatus, the skeletal member 5 can be impregnated with the resin while being placed on the flat surface of the metal belt 12, so that the weight of the impregnated resin is not loaded on the skeletal member itself, Even if the thickness of the material is extremely thin, the process failure that the skeleton material is broken by the weight of the resin can be solved, and stable production of the prepreg 1 using the thin skeleton material that was previously unusable can be achieved. It will be.

By adopting the manufacturing method described above, it is possible to use a non-woven fabric having a thickness of 70 μm or less and a woven fabric having a thickness of 30 μm or less, which cannot be conventionally used for a prepreg, as a skeleton material. As a result, a copper clad laminate can be manufactured using a thin prepreg using an extremely thin skeleton material. Since the skeleton material in the interlayer insulating layer is a non-woven fabric or an extremely thin woven fabric, this copper-clad laminate has good drilling workability with a carbon dioxide laser.

By applying the above-described manufacturing method and performing the operation performed on the surface of the work on the surface of the copper foil, the product in the state of the copper foil with the insulating layer can be easily obtained. is there. That is, in the claims, "a method for producing an insulating layer-provided copper foil having an insulating layer having a skeletal material impregnated with a thermosetting resin on one surface thereof, comprising: A method for producing a copper foil with an insulating layer, characterized in that a liquid resin film forming step of forming a liquid resin layer as a film having a predetermined thickness on one surface of a copper foil by using a liquid thermosetting resin. Preliminary drying step of drying the liquid resin layer on one side as it is to form a dry resin layer on the surface of the dry resin layer on one side of the copper foil,
Pre-bonding process for the skeleton material by stacking the skeleton materials, preheating and pressing to form a dry resin layer with skeleton material. A resin impregnation step of heating the resin at a temperature at which the resin can be reflowed while the dried resin layer with the skeleton material is placed on one surface of the copper foil to impregnate the skeleton material with the thermosetting resin component. When the resin impregnation is completed, the temperature is lowered immediately without completely curing the thermosetting resin, and the semi-cured state of the thermosetting resin impregnated into the skeleton is maintained to cool the copper foil with an insulating layer. Process. "
I am trying. The flow of this step is intentionally shown in FIGS. 6 to 8, but it can be expressed only by replacing the work plane of FIGS. 1 to 3 with the copper foil C. Therefore, the description of each step will be redundant and will not be repeated here.
By this manufacturing method, the copper foil 18 with an insulating layer in the state of the schematic cross section shown in FIG. 8 (5) can be obtained.

The insulating layer of the copper foil with an insulating layer obtained by such a manufacturing method includes a skeleton material, but the skeleton material is much thinner than that used for a conventional prepreg. It can be used, resulting in a thin insulating layer. Therefore, the copper clad laminate using this copper foil with an insulating layer can be made thin, and there are almost no defects such as breakage and cracking of the skeleton material. .

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the most preferred embodiment of the method for producing a prepreg according to the present invention will be described.

First Embodiment: In the present embodiment, a prepreg used in the production of a printed wiring board by a badge method in which a non-woven fabric made of aramid fiber having a thickness of 30 μm which is a skeleton material is impregnated with an epoxy thermosetting resin. The manufacturing method of No. 1 will be described. Hereinafter, the steps will be sequentially described with reference to FIGS. 1 to 3.

First, in a liquid resin film forming step as shown in FIG. 1A, a liquid epoxy thermosetting resin is used to form a flat surface on a work surface 2 having a size of 55 cm × 55 cm. 50 cm x 50 as a 16 μm thick coating
The liquid resin layer 3 was formed in the cm area. The liquid epoxy thermosetting resin used here is bisphenol A.
Type epoxy resin (trade name: YD-128, Toto Kasei Co., Ltd.) 30 parts by weight, o-cresol type epoxy resin (trade name: ESCN-195XL80, Sumitomo Chemical Co., Ltd.) 50 parts by weight, solid content as epoxy resin curing agent 16 parts by weight of dicyandiamide (4 parts by weight as dicyandiamide) in the form of a 25% dimethylformaldehyde solution, and 2-ethyl 4-methylimidazole as a curing accelerator (trade name:
Epoxy resin composition having a solid content of 60 wt% by dissolving 0.1 part by weight of Cazol 2E4MZ, manufactured by Shikoku Kasei Co., Ltd. in a mixed solvent of methyl ethyl ketone and dimethyl formaldehyde (mixing ratio: methyl ethyl ketone / dimethyl formaldehyde = 4/6) It was a thing.

Then, in the pre-drying step shown in FIG. 1B, the liquid resin layer 3 on the work plane 2 is
Let stand for 30 minutes at room temperature, and use a hot air drier for 15 minutes.
By blowing hot air at 0 ° C. for 2 minutes, the resin was dried to a semi-cured state to form a dry resin layer 4. The coating amount of the dry resin layer 4 at this time was 40 μm as the resin thickness after drying. As the work plane used here, a 1 cm-thick copper plate having a glossy surface was used.

Next, on the dry resin layer 4, a nominal thickness of 30
A non-woven fabric 5 of aramid fibers having a thickness of 50 μm and a size of 50 cm was laminated. This attachment is shown in Figure 2 (3).
The nonwoven fabric 5 is superposed on the surface of the dry resin layer 4 formed as shown in FIG.
A heating roll 6 capable of applying a laminating pressure of ² was pressed at a speed of 20 cm / min to form a dry resin layer 7 with a nonwoven fabric.

The dried resin layer 7 with a nonwoven fabric obtained as described above is placed in the heating furnace 8 as shown in FIG. 3 (4) while being placed on the work plane 2 and heated by the heater 9 to be dried. The constituent resin of the resin layer 4 was re-fluidized and impregnated into the non-woven fabric 5. It was decided to heat at a temperature of 150 ° C. in the heating furnace for 3 minutes.

When the resin impregnation is completed, FIG. 3 (5)
As shown in FIG.
The air blower 10 is provided with a plurality of clean air outlets, which are taken out from the heating furnace 8 while being placed on the work plane 2.
Due to this, the temperature of the blast was lowered. In this way, the thickness 50
A μm prepreg 1 was produced. The weight of the non-woven fabric in the weight of the prepreg 1 at this time was 25 wt%. In the above manufacturing process, no problem in the process was found, and the non-woven fabric 5
Naturally, there was no phenomenon of breaking.

Then, using this prepreg 1, an electrolytic copper foil with a carrier foil having an electrolytic copper foil layer having a nominal thickness of 3 μm on one surface thereof is pressed, and the carrier foil is removed to form a single-sided copper clad laminate. The board 10 was manufactured. The press processing conditions at this time are: a press temperature of 180 ° C. and a press pressure of 20 kg.
/ Cm ² , and the curing time was 90 minutes.

A 3 μm electrolytic copper foil layer of the single-sided copper-clad laminate obtained as described above was plated up to a thickness of about 18 μm by an electrolytic plating method, and the prepreg 1 was hardened on the base material side. A cured FR-4 substrate having a thickness of 100 μm was attached and reinforced with an adhesive to obtain a sample for peeling strength measurement. In this state, a 0.2 mm circuit was formed by an etching method and the peel strength was measured. As a result, the normal peel strength was 1.66 kgf / cm, and the peel strength after soldering was 1.58 kgf / cm, which was very good. It was showing the value.

Further, a blind via hole having a diameter of 100 μm was made 200 by using a carbon dioxide laser drilling machine while leaving a copper foil layer having a thickness of 3 μm of the copper clad laminate.
A drilling test was performed. The carbon dioxide laser irradiation conditions at this time were a frequency of 2000 Hz, a mask diameter of 5.0 mm,
Pulse width 60 μsec. , Pulse energy 16.0m
J, offset 0.8, laser beam diameter 130 μm,
This is done by planning to form a hole having a processing diameter of 100 μm. As a result, all 200 holes could be satisfactorily drilled, and the average hole diameter was 108 μm.

Second Embodiment: In this embodiment, the prepreg 1 is manufactured by using the continuous manufacturing apparatus 11 schematically shown in FIG.
Was manufactured. The width 52c is set on the metal belt 12 of the continuous manufacturing apparatus 11 which runs endlessly on an endless track.
The mirror-finished stainless steel belt with a thickness of 200 m and a running length of 10 m on one side was adopted. As shown in FIG. 4, the metal belt 12 is configured to travel at least consistently from the resin supply means to the temperature lowering means from the primary side to the secondary side in the process.

An edge coater type resin dispenser 13 is provided as a resin supply means at the primary end of the metal belt 12, and the same liquid thermosetting resin as used in the first embodiment is used. The resin dispenser 1
3 into the storage tank, and the resin is continuously supplied onto the metal belt 12 from the resin discharge portion, and the metal belt 12 is supplied onto the metal belt 12 continuously.
The liquid resin layer 3 was formed with a uniform thickness of 0 μm.

The liquid resin layer 3 formed on the metal belt 12 is run as a preliminary drying means arranged on the secondary side of the resin supply means at a distance of 1.5 m in a state of being naturally dried, and thereafter, By heating for a short time of 5 seconds in the drying zone 14, the liquid resin layer 3 on the metal belt 12 is changed to the semi-cured dry resin layer 4.

On the other hand, a skeleton material supplying means for continuously supplying the non-woven fabric 5 into the production line was arranged on the secondary side of the preliminary drying means. The skeleton material supplying means is configured to continuously feed the nonwoven fabric 5 having a width of 50 cm and a thickness of 70 μm from the skeleton material roll 15 to the dry resin layer 4 on the metal belt 12.
Was continuously supplied and superposed on the surface of the part. At this time, the feeding speed of the non-woven fabric 5 from the skeleton raw material roll 15 and the traveling speed of the metal belt 12 are 20
The non-woven fabric 5 was adhered uniformly in a plane and without generation of wrinkles by making the same in cm / min.

Then, a non-woven fabric pre-bonding means was arranged on the secondary side of the skeleton material supplying means. Using the heating roll 6 of this non-woven fabric pre-bonding means, the non-woven fabric 5 supplied from the skeleton material supplying means was continuously thermocompression bonded to the surface of the dry resin layer 4. The pressure bonding of the nonwoven fabric 5 by the heating roll 6 is 1
Only the resin in the surface layer of the dry resin layer 4 was refluidized by heating to 50 ° C. and a laminating pressure of 6 kg / cm ² was applied, and the dry resin layer 7 with a nonwoven fabric was formed. At this time, the resin of the dried resin layer 4 fluidized through the nonwoven fabric 5 did not exude.

On the secondary side of the non-woven fabric pre-bonding means, a heating zone 16 having a length of 60 cm was provided as a resin impregnating means. The portion of the non-woven fabric-attached dry resin layer 7 was heated for 3 minutes at a temperature of 150 ° C., which is lower than the curing temperature of the resin, using the heater 9 to re-fluidize the thermosetting resin and fluidize it. The non-woven fabric 5 to which the resin was stuck was sucked up and impregnated.

The part of the non-woven fabric 5 that has been impregnated with resin is
Upon exiting the heating zone 16, the air blower device 10 shown in FIG. 4 blows air for a distance of 3 m to lower the temperature, and a prepreg having a thickness of 90 μm is obtained.

Finally, a winding machine 17 for rolling the completed prepreg 1 on the secondary side of the temperature lowering means.
Was arranged as a means for collecting prepreg 1. As described above, the prepreg 1 having a width of 50 cm used for manufacturing a printed wiring board in which the nonwoven fabric 5 was impregnated with the thermosetting resin was continuously manufactured. The weight of the non-woven fabric in the weight of the prepreg 1 at this time was 25 wt%. By using this device, the non-woven fabric 5 was impregnated with the resin while being placed on the flat surface of the metal belt 12. Therefore, the weight of the impregnated resin was not applied to the non-woven fabric itself, and the thickness of the non-woven fabric 5 was increased. Is 7
Even if the thickness was 0 μm, the process failure that the nonwoven fabric 5 was broken by the weight of the resin did not occur, and it was possible to stably produce the prepreg 1 using the continuously thin nonwoven fabric as the skeleton material.

Using the prepreg 1 obtained here, a nominal thickness of 3 μm is formed on one surface of the prepreg 1 in the same manner as in the first embodiment.
The one-sided copper-clad laminate 1 is obtained by pressing the electrolytic copper foil with carrier foil having the electrolytic copper foil layer and removing the carrier foil.
0 was manufactured and the peel strength was measured. As a result, the peel strength under normal conditions was 1.63 kgf / cm, and the peel strength after soldering was 1.60 kgf / cm, which were very good values. Further, this copper clad laminate was subjected to a drilling test similar to that of the first embodiment using a carbon dioxide laser drilling machine. As a result, all 200 holes could be drilled well, and the average hole diameter was 109 μm. Met.

Third Embodiment: In this embodiment, a printed wiring board is manufactured by a badge method in which SP glass cloth, which is a woven cloth having a thickness of 15 μm, is used as a skeleton material and is impregnated with an epoxy thermosetting resin. The manufacturing method of the prepreg 1 used for the above will be described. Hereinafter, referring to FIGS. 1 to 3,
Each step will be described in order. The SP glass cloth, which is a skeleton material, uses the same reference numerals as those of the above-mentioned non-woven fabric, and the terms having common properties for convenience of explanation are the same as those of the first embodiment.

First, as in the first embodiment, FIG.
In the liquid resin film forming step as shown in, a liquid epoxy thermosetting resin is used, and a flat 55 cm × 55 cm
A liquid resin layer 3 was formed in a region of 50 cm × 50 cm as a film having a thickness of about 16 μm on the work surface 2 having a size of cm. Since the liquid epoxy thermosetting resin used here is the same as that in the first embodiment, detailed description thereof is omitted here.

Then, in the preliminary drying step shown in FIG. 1B, the liquid resin layer 3 on the work plane 2 is
Let stand for 30 minutes at room temperature, and use a hot air drier for 15 minutes.
By blowing hot air at 0 ° C. for 2 minutes, the resin was dried to a semi-cured state to form a dry resin layer 4. The coating amount of the dry resin layer 4 at this time was 15 μm as the resin thickness after drying. As the work plane used here, a 1 cm-thick copper plate having a glossy surface was used.

Next, on the dried resin layer 4, a nominal thickness of 15
A 50 cm × 50 cm size SP glass cloth 5 having a thickness of μm was laminated. This bonding is performed by superposing the SP glass cloth 5 on the surface of the dry resin layer 4 formed as shown in FIG.
A heating roll 6 capable of applying a laminating pressure of / cm ² was pressed at a speed of 20 cm / min to form an SP glass cloth-attached dry resin layer 7.

The dry resin layer 7 with SP glass cloth obtained as described above is placed on the work plane 2 as shown in FIG.
As shown in (4), it was placed in the heating furnace 8 and heated by the heater 9 to re-fluidize the constituent resin of the dry resin layer 4 and impregnate the SP glass cloth 5 with it. It was decided to heat at a temperature of 150 ° C. in the heating furnace for 3 minutes.

When the impregnation of the resin is completed, FIG. 3 (5)
As shown in FIG. 3, as a temperature lowering step, the resin impregnated SP glass cloth 5 is taken out from the heating furnace 8 while being placed on the work plane 2 and the air blower 10 is provided with an air blower 10 having a plurality of cleaned air outlets. It was Thus, the prepreg 1 having a thickness of 20 μm was manufactured. The weight of the non-woven fabric in the weight of the prepreg 1 at this time was 28 wt%. In the above manufacturing process, no process problems were observed, and naturally, there was no phenomenon that the SP glass cloth 5 as thin as 15 μm was broken.

Then, using this prepreg 1, an electrolytic copper foil with a carrier foil having an electrolytic copper foil layer having a nominal thickness of 3 μm on one surface thereof is pressed, and the carrier foil is removed to form a single-sided copper clad laminate. The board 10 was manufactured. The press processing conditions at this time are: a press temperature of 180 ° C. and a press pressure of 20 kg.
/ Cm ² , and the curing time was 90 minutes.

A 3 μm electrolytic copper foil layer of the single-sided copper clad laminate obtained as described above was plated up to a thickness of about 18 μm by an electrolytic plating method, and the prepreg 1 was hardened on the base material side. A cured FR-4 substrate having a thickness of 100 μm was attached and reinforced with an adhesive to obtain a sample for peeling strength measurement. In this state, a 0.2 mm circuit was formed by an etching method, and the peel strength was measured. As a result, the normal peel strength was 1.63 kgf / cm, and the peel strength after soldering was 1.61 kgf / cm, which was very good. It was showing the value.

Further, the laser workability was evaluated using a carbon dioxide laser drilling machine in the same manner as in the first embodiment. All 200 holes could be drilled well, and the average hole diameter was 101 μm. Met.

Fourth Embodiment: In the present embodiment, an insulating layer is provided by a badge method, which comprises an insulating layer obtained by impregnating a non-woven fabric using aramid fiber having a thickness of 30 μm, which is a skeleton material, with an epoxy thermosetting resin. A method of manufacturing the attached copper foil will be described.
Hereinafter, the steps will be sequentially described with reference to FIGS. 6 to 8.

First, as shown in FIG. 6 (1), in a liquid resin film forming step, a liquid epoxy thermosetting resin was used, and a 55 μm × 55 cm size 18 μm thick plate was placed on a flat surface. 5 as a film on the adhesive surface of the copper foil C
The liquid resin layer 3 was formed in an area of 0 cm × 50 cm. The liquid epoxy thermosetting resin used here is the first
The description is omitted because it is the same as that used in the embodiment.

Then, in the preliminary drying step shown in FIG. 6 (2), the liquid resin layer 3 on the work plane 2 is
Let stand for 30 minutes at room temperature, and use a hot air drier for 15 minutes.
By blowing hot air at 0 ° C. for 2 minutes, the resin was dried to a semi-cured state to form a dry resin layer 4. The coating amount of the dry resin layer 4 at this time was 40 μm as the resin thickness after drying. As the work plane used here, a 1 cm-thick copper plate having a glossy surface was used.

Next, on the dried resin layer 4, a nominal thickness of 30
A non-woven fabric 5 of aramid fibers having a thickness of 50 μm and a size of 50 cm was laminated. This attachment is shown in Figure 7 (3).
The nonwoven fabric 5 is superposed on the surface of the dry resin layer 4 formed as shown in FIG.
A heating roll 6 capable of applying a laminating pressure of ² was pressed at a speed of 20 cm / min to form a dry resin layer 7 with a nonwoven fabric.

The non-woven fabric-attached dry resin layer 7 obtained as described above is placed on the copper foil C, placed in a heating furnace 8 as shown in FIG. 8 (4), and heated by a heater 9. The constituent resin of the dry resin layer 4 was re-fluidized and impregnated into the nonwoven fabric 5.
It was decided to heat at a temperature of 150 ° C. in the heating furnace for 3 minutes.

When the resin impregnation is completed, FIG. 8 (5)
As shown in FIG. 5, in the temperature lowering step, the air blower 10 having a plurality of outlets for the cleaned air is used to cool down the airflow, and the copper foil with an insulating layer 18 having an insulating layer with a thickness of 50 μm is provided.
Was able to be manufactured. The weight of the nonwoven fabric in the insulating layer at this time was 25 wt%.

[0074]

By using the method for producing a prepreg according to the present invention, a nonwoven fabric having a thickness of 70 μm or less or a woven fabric having a thickness of 30 μm or less, which cannot be mass-produced by the conventional method for producing a prepreg, is used. Enables stable production of prepreg. Therefore, it is possible to secure excellent laser drilling processability obtained by using a non-woven fabric as a skeleton material, and to provide a prepreg using a thin non-woven fabric or woven fabric, which has never been obtained before. Further, by applying this prepreg manufacturing method, it becomes possible to easily supply the copper foil with an insulating layer provided with a very thin insulating layer, and to manufacture the thin printed wiring board easily.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a flow of a method of manufacturing a prepreg according to the present invention.

FIG. 2 is a schematic diagram for explaining a flow of a method of manufacturing a prepreg according to the present invention.

FIG. 3 is a schematic diagram for explaining a flow of a method of manufacturing a prepreg according to the present invention.

FIG. 4 is a schematic side view for explaining the layout concept of the continuous prepreg manufacturing apparatus according to the present invention.

FIG. 5 is a schematic view showing a conventional prepreg manufacturing method.

FIG. 6 is a schematic diagram for explaining a flow of a method of manufacturing a prepreg according to the present invention.

FIG. 7 is a schematic diagram for explaining a flow of a method of manufacturing a prepreg according to the present invention.

FIG. 8 is a schematic diagram for explaining a flow of a method of manufacturing a prepreg according to the present invention.

[Explanation of symbols]

1 prepreg 2 Work plane 3 Liquid resin layer 4 Dry resin layer 5 non-woven fabric 6 heating rolls 7 Dry resin layer with non-woven fabric 8 heating furnace 9 heater 10 Air blower 11 Continuous manufacturing equipment 12 metal belt 13 resin dispenser 14 Drying zone 15 Skeletal material roll 16 heating zone 17 Winder 18 Copper foil with insulating layer C copper foil

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F072 AA01 AA07 AB06 AB09 AB11                       AD11 AD23 AG03 AH00 AH21                       AH22 AJ00 AJ04 AJ11 AJ19                       AK02 AK05 AL12 AL13                 4F100 AB17B AB33B AG00A AK01A                       AK47A AK53 BA02 DG01A                       DG11A DG15 DH01A EC01                       EC012 EH46 EH462 EJ17                       EJ172 EJ42 EJ422 EJ50                       EJ502 EJ82 EJ822 EJ86                       EJ862 GB43 JB13A JG04A                       JL01

Claims (6)

[Claims] 1. A method of manufacturing a prepreg used for manufacturing a printed wiring board in which a skeletal material is impregnated with a thermosetting resin, the method comprising the steps of to: Method. A liquid resin film forming step of forming a liquid resin layer as a film having a predetermined thickness on a flat work plane using a liquid thermosetting resin. A pre-drying process in which the liquid resin layer on the work plane is dried as it is to form a dry resin layer. A skeleton material pre-bonding step of forming a skeleton material-dried resin layer by superposing a skeleton material on the surface of the dry resin layer on the plane of the work, preheating and pressing. A resin impregnation process in which the dried resin layer with the skeleton material is placed on the work plane and heated at a temperature at which the resin can reflow to impregnate the skeleton material with the thermosetting resin component. When the resin impregnation is completed, the temperature is lowered immediately without completely curing the thermosetting resin, and the thermosetting resin impregnated into the skeletal material is maintained in a semi-cured state to become a prepreg state. . 2. A metal belt which runs endlessly on an endless track, a resin supply means for forming a thermosetting liquid resin layer on the metal belt, and a pre-drying means for making the liquid resin layer a dry resin layer. A skeleton material supplying means for continuously supplying the skeleton material into the production line; a skeleton material pre-bonding means for preliminarily crimping the skeleton material to the dry resin layer; and a preliminarily crimping skeleton material to the dry resin layer. A manufacturing line comprising a resin impregnating means for heating a part to impregnate the resin, a temperature lowering means for performing a temperature lowering operation after completion of the resin impregnation to obtain a prepreg state, and a means for collecting the completed prepreg into one production line. A manufacturing apparatus used for carrying out the manufacturing method of the prepreg described, wherein the metal belt is in the process from the primary side to the secondary side,
At least consistent running from the resin supply means to the temperature lowering means is performed, and the resin supply means continuously supplies a liquid thermosetting resin onto the metal belt to provide a uniform predetermined thickness on the metal belt. A resin dispenser capable of forming the liquid resin layer of the metal belt is disposed at the primary end of the metal belt, and the liquid resin layer on the metal belt is dried on the secondary side of the resin supply means. A drying zone for performing heat drying or air drying is arranged as a preliminary drying means for forming a layer, and on the secondary side of the preliminary drying means, continuous from the skeleton raw material roll in synchronization with the traveling speed of the metal belt. A skeleton material supplying means for feeding the skeleton material is disposed on the secondary side of the skeleton material supplying means, and the skeleton material supplied from the skeleton material supplying means is heated on the surface of the dry resin layer on the metal belt. A skeleton material pre-adhesion means for placing the skeleton material in a dry resin layer state by thermocompression using a roll is provided, and a portion of the dry resin layer pre-bonded with the skeleton material is provided on the secondary side of the skeleton material pre-adhesion means. Is heated at a temperature equal to or lower than the curing temperature of the resin to cause the thermosetting resin to re-fluidize, and a heating zone for impregnating the fluidized resin into the skeleton material bonded is provided as the resin impregnating means. On the secondary side, a temperature lowering operation is performed after completion of resin impregnation to leave the prepreg in a state of standing cooling or forced cooling, thereby maintaining the semi-cured state of the thermosetting resin impregnated in the skeleton material and the prepreg state. A cooling device for prepreg is arranged on the secondary side of the temperature lowering means, and a cutting device for winding the completed prepreg into a roll or a cut sheet is arranged as a means for collecting the prepreg. Continuous production apparatus for a prepreg used for manufacturing a printed wiring board impregnated with thermosetting resin in skeletal material that. 3. A prepreg used for manufacturing a printed wiring board, wherein a skeletal material manufactured by the manufacturing method according to claim 1 is impregnated with a thermosetting resin, and the skeletal material has a nominal thickness of 70 μm or less. A prepreg, which is a non-woven fabric using aramid fiber or glass fiber having a thickness of 1. 4. A prepreg used for manufacturing a printed wiring board, wherein a skeletal material manufactured by the manufacturing method according to claim 1 is impregnated with a thermosetting resin, and the skeletal material has a nominal thickness of 30 μm or less. A prepreg characterized by being a glass cloth having a thickness of. 5. A method for producing a copper foil with an insulating layer, which comprises an insulating layer having a skeletal material impregnated with a thermosetting resin on one side, the method comprising the steps of: Manufacturing method of copper foil with insulating layer. A liquid resin film forming step of forming a liquid resin layer as a film having a predetermined thickness on one surface of a copper foil using a liquid thermosetting resin. A pre-drying step in which the liquid resin layer on one side of the copper foil is dried as it is to form a dry resin layer. A skeleton material pre-bonding step of forming a skeleton material-dried resin layer by superimposing a skeleton material on the surface of the dry resin layer on one surface of the copper foil, preheating and press-bonding. A resin impregnation step of heating the resin at a temperature at which the resin can be reflowed while the dried resin layer with the skeleton material is placed on one surface of the copper foil to impregnate the skeleton material with the thermosetting resin component. When the resin impregnation is completed, the temperature is lowered immediately without completely curing the thermosetting resin, and the semi-cured state of the thermosetting resin impregnated into the skeleton is maintained to cool the copper foil with an insulating layer. Process. 6. A copper foil with an insulating layer obtained by the manufacturing method according to claim 5.